5-Amino-1-(2,6-dichloro-4-trifluoromethyl-phenyl)-3-[3H3]-methylsulfanyl-1H-pyrazole-4-carbonitrile (CTOM): Synthesis and Characterization of a Novel and Selective Insect GABA Receptor Radioligand

Pyrazole 2a is a novel, potent ligand for insect GABA receptors obtained from housefly head membrane preparations (Ki=8 nM). It is 500-fold selective against the mammalian receptor (mouse brain preparations). Its specifically tritiated version (2b) was synthesized by reduction of disulfide 10 with NaBH4 followed by alkylation with [3H3]-CH3I.